1. Field of the Invention
This invention relates to a novel motor drive device for a camera.
2. Description of the Prior Art
The motor drive devices heretofore used are known to perform the following functions. A rotatable cam biased by a spring in the thrust direction is rotated by a motor. When a roller lies on one of the ramps of the projected portion of the rotatable cam which is projected in the thrust direction, the roller is moved by that ramp to effect film advance. When the roller tries to stop due to an increased film advance load upon completion of film advance, the roller rides onto the projected portion to stop the motor. When the shutter button is again depressed simultaneously therewith to supply power to the motor, the rotatable cam begins to rotate and the roller rolls down the other ramp of the projected portion to effect shutter release. In these devices, however, the roller for effecting film advance and detecting the completion of film advance is always brought into contact with the cam by the spring force and this may cause some residual torque to remain in the spring at the completion of film advance. Therefore, when shutter release is effected by the shutter button, vibration thereof may undesirably cause the residual torque in the spring to be transmitted to the film to vibrate the image plane during photography.